Photogravure-printing machine



. July 30, 1929. w. GREAVES PHOTOGRAVURE PRINTING MACHINE Filed 001- 1927 Patented July 30, 1929.

UNITED STATES 1,722,961 PATENT OFFICE.

.WILFRED GREAVES, 0F SHADWELL, NEAR LEEDS, ENGLAND, ASSIGNOR TO LINOTYPN AND MACHINERY LIMITED, 01 LONDON, ENGLAND.

rnoroenavvna-rnmrma Madame.

Application filed October 3, 1927. Serial No. 223,775, and in Great Britain October 13, 1928.

said plate cylinder, the chief object being to provide a simple and effective two revolution photogravure printing machine.

According to the invention, the upper or impression cylinder is adapted to be liftedout of contact with the other or plate cylinder during every alternate revolution by means of a cam. adapted to operate on orcontrol appropriate arms connected to or associated with an eccentric bush on the upper cylinder.

' In order that the invention may be clearly understood and readily carried into effect, the same will now be more fully described with reference to and by the aid of the accompanying drawings;.wherein v Figure 1 is a longitudinal section ofa photogravure printing machine according to the invention,

Figure 2 is a sectional view of the plate cylinder of the machine.

Referringto the drawings, themachine comprises an impression cylinder 1, and a plate cylinder 2 around which latter the photogravure plate 3 is drawn and held during the operation of the machine. Oneedge of the plate 3 is secured within a groove or slot 4 in the plate cylinder 2 by means of a wedge-shaped clamping bar 5 having associated clamping screws 6.- The other end of the plate 3 is secured by a clamp actuated bybolts 7 to a block 8 slidable on a guide bracket 9 located in a groove or slot 10 in the plate cylinder 2, said block 8 being adjustable'on said bracket 9 by means of an'associatcd screw 11 so as to draw and maintain the plate 3 taut around the plate cylinder 2. Between the plate cylinder 2' and plate 3.is a lining 12 adapted to absorb any ink which may have a tendency to pass between the plate 3 and cylinder 2. Such lining 12 may consist of paper, fabric or other appropriate non-resilient material which Will serve as a lining or backing material to the plate 3 and act as a preventative againsjan excess of ink being collected between the plate 3 and cylinder 2. The upper or impression cylinder 1 is fitted with grippers 13 adapted to take the sheet "fed from the table 14 and convey it .into contact with the plate cylinder 2 to take the impression. The arrangement is such taken, whilst during the second revolution the printed sheet is delivered printed face up wards onto tapes 15 to be carried forward by the usual grasshopper feed 16 on to a delivery table 17. Thus, a cam 18is provided adapted to operate or control appropriate lever and link mechanism 19 associated with an eccentric bush 20 on the upper cylinder -1 to' may be reciprocated in any appropriate man-- ner to prevent scratching of the engraved plate 3.

Whereas in previously proposed photogravure machines, it has been a common fault that a mark was caused by'the vibration of the two cylinders when their surfaces were being brought into contact, this difliculty may be overcome in the machine above described by arranging that the cylinder bearers come into contact when the gaps are opposite to one another. The bearers of at least one of the cylinders have their peripheries shaped otherwise than as figures of revolution about the axis of said cylinder, to permit the pressure between the cylinders to be increased gradually so that they may be brct a;'htv into contact or rolled in with a gradual radius, thereby causing no vibration as there is then no resistance. Such an arrangement is illustrated in Figure 2, wherein it will be seen that the periphery of each bearer 24 at the part corresponding with the gap in the plate cylinder 2, is an arc of a circle struck from a cen-' tre b which, in the representation given in Figure 2, is below the centre a of the plate cylinder itself, so that the bearer at the part in question will be of somewhat flattened contour as compared with the remainder of the periphery of the said bearer. The bearers of the impression cylinder 1 may be truly circular throughout, or may be of the same form as the bearers of the plate cylinder.

I am aware it has before been proposed in a two revolution intaglio printing machine that during one revolution the 1mpress1on is employing a gripper cylinder and acopper or other roller,,to raise the gripper cylinder out of contact with the intaglio printing roller during the second or delivery rotation of said gripper cylinder.

I am also aware it has before been proposed in photogravure printing machines to place a rubber or other resilient blanket beneath the plate on the cylinder to permit of the surface of the plate being efliciently cleaned by a doctor roller, said blanket serving as a cushioning means sothat the doctor roller will sink slightly into'the plate.

I claim 1. In a two revolution photogravure printing machine, the combination with an impression cylinder and a plate cylinder, one adapted to be moved into and out of printing relationship to the other, of bearers on the respective cylinders adapted to engage inmutual rolling contact, the bearers of at least one of the cylinders having their peripheries shaped otherwise than as figures of revolution about the axis of the said cylinder.

2. In a two revolution photogravure printing machine, the combination of an impression cylinder, having a gap, sheet'grippers operative within the gap, a plate cylinder having a gap, the two cylinders being movable one relatively to the other into and out of printing contact, a printing plate clothing the plate cylinder and ten minating at its leading and following edges in the plate cylinder gap, the gaps of the two cylinders registering with each other during their rotation,

bearers on the respective cylinders adapted to engage in mutual rolling contact, the bearers of at least one of the cylinders having their peripheries shaped otherwise than as figures of revolution about the axis of said cylinder, an inking roller and a doctor contacting with the plate on respectively-opposite sides of the plate cylinder, and a lining interposed between the plate cylinder and plate, of nonresilient absorbent material for producing an ink-tight joint between said cylinder and plate.

WILFRED GREAVES. 

